Spin-charge separation at small length scales in the 2D t-J Model

W.O. Putikka

Claudius Gros, Roser Valentí

We consider projected wave functions for the two-dimensional t-J model. For various wave functions, including correlated Fermi-liquid and Luttinger-type wave functions, we present the static charge-charge and spin-spin structure factors. Comparisons with recent results from a high-temperature expansion by Putikka et al. indicates spin-charge separation at small length scales.

Zheng-Yu Weng, D. N. Sheng, C. S. Ting

Nandini Trivedi, Mohit Randeria

We show that there are qualitative differences between the temperature dependence of the spin and charge correlations in the normal state of the 2D attractive Hubbard model using quantum Monte Carlo simulations. The one-particle density of states shows a pseudogap above ${T}_{c}$ with a depleted $N\left(0\right)$ with decreasing $T$. The susceptibility ${\ensuremath{\chi}}_{s}$ and the low frequency spin spectral weight track $N\left(0\right)$, which explains the spin-gap scaling: ${1/T}_{1}T\ensuremath{\sim}{\ensuremath{\chi}}_{s}\left(T\right)$. However, collective excitations contribute to the charge channel, and the compressibility $dn/d\ensuremath{\mu}$ is $T$ independent. This anomalous ``spin-charge separation'' is shown to exist even at intermediate $|U|$ where the momentum distribution $n\left(\mathbf{k}\right)$ gives evidence for a degenerate Fermi system.

W. O. Putikka, Marco U. Luchini, R. R. P. Singh

Tetsuo Matsui